Any tour of Gettysburg begins with the museum, where they have a wonderful collection of artifacts, as well as a gift shop where you can buy the audio CD to accompany you on a driving tour.
Much of the action of the battle of Gettysburg surrounded Little Roundtop, and in particular, repeated attacks by the Texas forces coming from the Devil's Den. Here is a view from Little Roundtop, where you can see the Devil's Den (rock formation) off to the left.
This was the first time we'd seen a chestnut tree. It was a big 'un.